FIBRONECTIN-BINDING AND CELL-SURFACE HYDROPHOBICITY CONTRIBUTE TO ADHERENCE PROPERTIES OF GROUP-B STREPTOCOCCI

The matrix protein, fibronectin, which is detectable in various tissue s, when present in the Vaginal fluid of women in labour, indicates the rupture of membranes. It is known that many bacteria adhere to fibron ectin, thus establishing a first step of infection. In women in labour , group B streptococci are common agents of chorioamnionitis. For grou p B streptococci, unspecific adherence mechanisms like negative net ch arge and hydrophobic interactions have already been discussed in liter ature. In the present study, group B streptococci isolates from 57 pat ients with premature rupture of membranes were studied for fibronectin binding activities, using a particle agglutination assay and for cell surface hydrophobicity, by testing adhesion to hydrocarbons. Particle agglutination assays and adhesion assays were done with strains grown on blood-containing media and media without blood. Fibronectin bindin g was shown to be present in 14 and 11 out of 57 isolates grown on Mue ller-Hinton and Tryptic Soy agar, respectively. When the strains were grown on blood-containing media, fibronectin-binding was found to be c oncomitant with decreased hydrophobicity. According to the results obt ained in a total of 57 strains, cell surface hydrophobicity is an unsp ecific adhesion factor in group B streptococci. Fibronectin binding se ems to be an additional adherence factor in some of the strains and ma y be assumed to play a major role in establishing infectious processes .